Can I reduce the capital gain on which I have to pay taxes if the previous year I had big losses?

Suppose this year I have a capital gain of 200 thousand pounds, but last year I had a loss of 50 thousand pounds… this year can I pay taxes only on 150 thousand pounds of capital gain?

And what if the events happen in the opposite order: suppose last year I had a capital gain of 200 thousand pounds and I paid taxes on that, and this year I have 50 thousand pounds of losses. Can I get money back for overpaid taxes? Or reduce capital gain on which to pay taxes next year?

I’m asking as I’m investing in cryptocurrency, but I think the same apply to any type of investment.